High Flow secondary cats and effects on drone

Stucks · 11-22-2013, 07:19 AM

A couple of months ago, I bought a slightly used ets exhaust system for my e92 335i. Its a dual 2.5 inch system with an x pipe, and separate mufflers/exits. I was running the factory e92 335i catback before with stock secondary cats in place + catless downpipes. Now that I am fully catless, the more freeflowing exhaust has def provided a nice midrange gain....and it actually idles around the same sound level as the stock exhaust did, only maybe a tad bit louder.

Thing is, at first I was alright with the fuel smell, and I kind of still don't mind. The interior pieces of the car do tend to make noise/rattle at a certain rpm due to drone, mainly the center console. I rode in a friends rb turbo 335i yesterday who had a custom dual 2.5 inch exhaust to an x pipe, to bastuck muffler, with some 300 or 400 cell cats welded in the midpipes. Not a peep as far as noise is concerned from the interior pieces of the car. No drone. Before, without the cats, he said his car droned horribly.

Question is, I found some 100 and 200 cell race cats from mbs. I want to restrict flow as little as possible, but am unsure of which cats I should order that would help eliminate some of the drone/interior rattling. Any ideas or experiences?! Thoughts? Thanks!

http://www.mandrelbendingsolutions.c...High%2C/Detail

enrita · 11-22-2013, 08:55 AM

i have 100 cell race cats from HJS. perfect. i pass emissions and sound is good no drone.

R.G. · 11-23-2013, 12:23 AM

I have high flow secondaries installed AND 4, yes 4 resonators and I still get a bit of interior rattle at low rpm. Hate it. I can drive a bit more aggressive and it's not there. Just sold my Dinan cans to install my second set of resonators in their place. Had zero drone with two resonators, high flow secondaries and the Dinan cans.

xtrackdog · 11-23-2013, 08:39 AM

Did I understand correctly that you experienced drone with the ETS system?

Stucks · 11-24-2013, 04:27 AM

Quote:

Originally Posted by xtrackdog

Did I understand correctly that you experienced drone with the ETS system?

only for a couple hundred rpms on my 6at car. other systems drone much worse.

xtrackdog · 11-24-2013, 10:11 AM

Whew. Glad you posted this.

11-22-2013, 07:19 AM	#1
Stucks Lieutenant Colonel 180 Rep 1,911 Posts Drives: 2017 F30 340i Xdrive Join Date: Oct 2010 Location: Montgomery County, MD iTrader: (12)	High Flow secondary cats and effects on drone A couple of months ago, I bought a slightly used ets exhaust system for my e92 335i. Its a dual 2.5 inch system with an x pipe, and separate mufflers/exits. I was running the factory e92 335i catback before with stock secondary cats in place + catless downpipes. Now that I am fully catless, the more freeflowing exhaust has def provided a nice midrange gain....and it actually idles around the same sound level as the stock exhaust did, only maybe a tad bit louder. Thing is, at first I was alright with the fuel smell, and I kind of still don't mind. The interior pieces of the car do tend to make noise/rattle at a certain rpm due to drone, mainly the center console. I rode in a friends rb turbo 335i yesterday who had a custom dual 2.5 inch exhaust to an x pipe, to bastuck muffler, with some 300 or 400 cell cats welded in the midpipes. Not a peep as far as noise is concerned from the interior pieces of the car. No drone. Before, without the cats, he said his car droned horribly. Question is, I found some 100 and 200 cell race cats from mbs. I want to restrict flow as little as possible, but am unsure of which cats I should order that would help eliminate some of the drone/interior rattling. Any ideas or experiences?! Thoughts? Thanks! http://www.mandrelbendingsolutions.c...High%2C/Detail __________________ Current: 2017 F30 340i xdrive Previous: 2008 e92 335i coupe: RB turbos, mach 116 race fuel, methanol, alot of boost. Previous: 2003 Honda Accord V6 coupe: AEM V2, zex 75 wet shot (sold)
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11-22-2013, 08:55 AM	#2
enrita Major General 163 Rep 7,377 Posts Drives: 335i - Big turbos Join Date: Sep 2008 Location: Italian in Sweden iTrader: (0)	i have 100 cell race cats from HJS. perfect. i pass emissions and sound is good no drone. __________________ 07 335i AT - MOTIV 750 - MHD E85 BMS flash - BMS PI - JB4G5 - Okada Coils - NGK 5992 Plugs - Helix IC - Snow Stg. 3 - Stett CP - Custom midpipes with 100 HJS Cats - Bastuck Quad - PSS10 - QUAIFE LSD - BMS OCC - Forge DVs - AR OC - ALCON BBK - M3 Chassi - Dinan CP - Velocity M rear Toe arms - Advan RZ-DF - LUX H8 - Level 10 AT upgrade
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11-23-2013, 12:23 AM	#3
R.G. Captain 240 Rep 885 Posts Drives: Isetta Join Date: Jan 2013 Location: In my sub conscious iTrader: (12)	I have high flow secondaries installed AND 4, yes 4 resonators and I still get a bit of interior rattle at low rpm. Hate it. I can drive a bit more aggressive and it's not there. Just sold my Dinan cans to install my second set of resonators in their place. Had zero drone with two resonators, high flow secondaries and the Dinan cans. __________________ DocRace 6266 E92. M8 comp coupe, X5m
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11-23-2013, 08:39 AM	#4
xtrackdog Private 6 Rep 62 Posts Drives: 2008 335i Join Date: Dec 2011 Location: Oregon iTrader: (0)	ETS system Did I understand correctly that you experienced drone with the ETS system?
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11-24-2013, 10:11 AM	#6
xtrackdog Private 6 Rep 62 Posts Drives: 2008 335i Join Date: Dec 2011 Location: Oregon iTrader: (0)	Whew. Glad you posted this.
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